What should I do?

I'm sorry, I know this will not be a popular post. But if you paid $500 based on the pictures you posted, a lot of the blame falls on you. I would not have purchased any of the three dashes I saw based on those photos. If you asked for more photos, fine, but if you didn't, you pretty much got what you saw.
Those are the pictures the OP took of what he got, not from the ad.